Method of making inductive windings



P 21, 1936- L. G. KETCHAM 2,038,297

METHOD OF MAKING INDUCTIVE WINDINGS Filed Sept. 12, 1934 Patented Apr. 21, 1936 UNITED STATES PATENT OFFICE METHOD OF MAKING INDUCTIVI] WINDINGS Lyman G. Ketcham, Brooklyn, N. Y., assignor to Telerarlio Engineering Corporation, New York, N. Y., a corporation of New York Application September 12, 1934, Serial No. 743,711

8 Claims. (Q1. 175-359) This invention relates to improvement in tions balances with the fixed standard. When methods of making inductive windings.

Heretofore inductive windings have been made in one unitary section and in'order that the inductance of such a winding could be determined with some degree of accuracy, the winding would be provided with a number of turns in excess of what would be expected to be sufilcient for the required inductance. The unitary winding could then be checked against a standard by connecting the ends of the wire to a test apparatus and by successively winding oif extra turns and making tests until the inductance reached approximately the desired figure. Naturally, such procedure involves considerable cost both in time and material and the inductance could never be determined with more than a fair degree of accuracy.

An object of the invention is to provide improved windings of the maximum accuracy so far as their inductance is concerned.

Another object of the invention is to provide methods for making windings in which the inductance can be accurately determined.

In the practice of the present invention, windings are made in more than one section instead of one section, and initially one section is movable relative to the other section or sections, so that the inductance of the total winding can be accurately determined. For example, a winding may be made in two sections; one section being rigidly fastened to the rod or spool of insulating material upon which the winding is mounted, and the other section being initially movable along such rod or spool. Due to this movement, it is possible to adjust the movable winding relative to the fixed winding until the inductance of the two sections reaches the desired amount, at which time the movable section may be permanently secured to the rod or spool. In order that a winding of this character may be produced the following steps are carried out; the first section is wound directly and permanently onto the rod or spool and then a sheath of thin material is positioned on this rod or spool, and the wire of the first section is then continued and wound into the second section with the sleeve in place. This sheath'may totally or partially surround the rod as conditions warrant. When the winding of the second section has been completed, the sheath is removed and due to the space occupied by the sheath, the second section can be moved, within limits, along the rod or spool. The two sections are then compared with a standard inductance and the movable section moved relative to the fixed section until the inductance of the two secsuch position has been reached, the initial movable section is permanently secured to the rod or spool by means of some quick drying waterproof lacquer. If desired, the winding may be made in more than two sections, in practice it having been found that under certain conditions a winding of three or four sections or even more will produce admirable results.

Other features, objects and advantages of the 10 invention will become apparent by reference to the following detailed description taken in conjunction with the accompanying drawing illustrating the invention, wherein Fig. l is a vertical section of a winding during the process of manufacture.

Fig. 2 is an end view of the winding during the process of manufacture; and

Fig. 3 is a view similar to Fig. 1 illustrating the division of a winding into'more than two sections during manufacture.

Referring now to the drawing and particularly to Figs. 1 and'2, It! indicates a rod or spool of some suitable insulating material such as wood, fibre, ceramic material, etc., upon which a winding is to be mounted. The wire II is shown as being wound into a self-supporting coil I2 after which the wire is further wound into a self-supporting coil I4. The two coils, as indicated, are in series aiding relation. A sheath I5 of thin material is shown as partially surrounding the rod III with the coil I4 wound upon the rod and the sleeve.

In constructing the winding in sections, the

wire II is first wound tightly upon the rod I0 to form the coil I2. .As the coil I2 is completed, the turns thereof are locked in place by some suitable quick drying cement, and then the wire II is further wound into the coil I4, around the rod I0 and the sheath I5. When this coil has 40 been completed and the turns thereof locked against unwinding, the sleeve I5 is withdrawn. The withdrawal of the sheath I5 necessarily causes the coil I4 to fit somewhat loosely on the rod I0 so that this coil can be moved around and longitudinally of the rod within the limits set up by the length of wire between the two coils I2 and I4.

The two terminals of the two sections of the total winding are then connected to test apparatus for comparison with an inductance of known value. This section I4 is then moved toward or away from the section I2 until the inductance of the two sections matches that of the standard. When this condition has been reached, the section H is locked to the rod Ill by application of some suitable quick-drying nonhygroscopic cement.

If desired, the winding may be made in more than two sections, such a winding being illustrated in Fig. 3 wherein the winding is shown as being made up of sections 20, 2|, 22 and 23. the manufacture of this winding, sections 20, 2| and 22 are wound tightly onto the rod l0 while the section 23 is wound in the same fashion as the section ll, use being made of a sleeve I5. With this single movable section, the inductance of the entire winding can be accurately determined in the manner set forth hereinbefore.

From the foregoing it will be seen that a winding constructed in the manner set forth possesses the advantage that it can be manufactured much more quickly than can windings of single sections manufactured in the manner set forth previously. The cost of manufacturing this improved winding naturally is considerably less than the cost of manufacturing a single section winding according to prior practice. However, in addition to the advantages inherent in this winding so far as accuracy, speed of manufacture and reduction of cost of manufacture, the improved winding of the invention possesses other advantages. For example, if a winding is made in two or more sections, the distributed capacity of the entire winding is materially reduced as compared with a single section winding or similar inductance with accompanying advantages. If the winding is made in two sections the distributed capacity will be cut approximately in half. If the winding is made in three sections, the distributed capacity of the entire winding will reach approximately one-third of the distributed capacity of a single section winding of the same inductance. Another advantage inherent in this type of construction resides in the fact that the use thereof in a circuit reduces the effective resistance of the circuit at high frequency. Consequently, the frequency range of a circuit can be materially increased by utilizing a winding embodying the present invention.

When the value of an inductance in certain uses need not be determined as accurately as is made possible by the above described operation, beneficial results will be obtained by utilizing a sectional winding wherein all of the sections are initially permanently secured to the core. The number of turns in each section can be predetermined with suflicient accuracy as to cause the inductance of the complete winding to come within the allowed range. Such a winding possesses proportionate advantages in the reduction of distributed capacity and in the reduction of the efiective resistance of the circuit in which the winding is used.

From the foregoing it will be seen that improved windings of the invention possess advantages not found in windings heretofore utilized. Furthermore, the method of making the improved windings of this invention serves to materially reduce the time required for making a winding of a desired inductance; reduces the cost of manufacturing the windings; and makes possible the production of a winding, the inductance of which can be determined more accurately than is possible with prior practices. It will be understood that the invention is not to be limited to the illustrated embodiments, but is to be limited only by the scope of the following claims.

I claim:

1. The method of making a winding of desired inductance which comprises forming a continuous wire conductor into a sectional winding on a core of insulating material with one section wound upon the core and upon a sheath at least partially surrounding the core, removing the sheath from the core whereby the section initially wound on the sheath can be movedon the core, moving said movable section on the core until the inductance of the entire winding reaches the desired value, and securing said movable section to the core in the adjusted position.

2. The method of making a winding of desired inductance which comprises winding a continuous wire conductor onto a core of insulating material to form a coil immovable on the core, winding said conductor around the core and a sheath at least partially surrounding the core into the form of a second coil, removing said-sheath to permit movement of the second coil on the core, moving the second coil relative to the first coil until the inductance of the entire winding reaches the desired value, and securing the second coil to the core in the adiusted position.

3. The method of making a winding of desired inductance which comprises winding a continuouswire conductor onto a core of insulating material to form coils immovable on the core, winding said conductor onto the core and a sheath at least partially surrounding the core to form a final coil, removing the sheath from the core to permit movement of the final coil on the core, moving the final coil on the core until the inductance of the entire winding reaches the desired value, and securing the final coil to the core in the adjusted position.

4. The method of making a winding of desired inductance which comprises winding a continuous wire conductor onto a core of insulating material to form self-supporting coils in series-aiding relation immovable on the core, winding said conductor into a final coil movable on said core, said final coil being in series-aiding relation to the immovable coils, the turns of wire in the entire winding being of such num her as to cause the winding to have approximately the desired inductance, moving said final coil on the core until the inductance of the entire winding reaches the desired value, and securing the final coil to the core in the adjusted position.

5. The method of making a winding of desired inductance on a core of insulating material which comprises so forming a continuous wire conductor on the core into a sectional multi-selfsupporting coil winding that one coil of said winding is movable on the core and the remainder of said winding is fixed to said core, moving said movable coil relative to the fixed part of the winding until the inductance of the entire winding reaches the desired value, and securing said movable coil to said core in the adjusted position.

6. The method of making a winding of desired inductance on a core of insulating material which comprises so forming a continuous wire conductor on the core into a series-aiding sectional multi-self-supporting coil winding that one coil of said winding is movable on the core and the remainder of said winding is fixed to said core, the turns of wire in the entire winding being of such number as to cause the winding to have approximately the desired inductance, moving said movable coil relative to the fixed part of the winding until the inductance of the entire winding reaches the desired value, and securing said movable coil to said core in the adjusted position.

7. The method of making a winding oi desired inductance on a core of insulating material which comprises winding a continuous wire conductor onto the core to form a sell-supporting coil fixed to the core, winding the conductor onto the core to form a second self-supporting coil in seriesaiding relation to said first coil, said second coil being movable relative to the first coil, moving the second coil on the core until the inductance of the two coils reaches the desired value, and securing the movable coil to the core in the ad- Justed position.

the adjusted position.

8. The method of making a winding of desired inductance which comprises forming a continuous wire conductor into a sectional winding on a core of insulating material with a movable section wound upon the core and upon a sheath at least partially surrounding the core, the turns of wire in the entire winding being of such number as to cause the winding to have approximately the desired inductance, moving said movable section on the core until the inductance of the entire winding reaches the desired value, and securing said movable section to the core in 

